From the introduction: While this adventure is not part of Old-School Adventures Old School Adventures Module VA1: Valley of the Five Fires, it has been designed to be used in conjunction with the setting it creates. Furthermore, its format allows use with almost any early edition of the original role-playing game (Oe, BX, 1e) or comparable retro-clone (e.g., S&W, LL), but may require some tweaking to match your chosen rules edition.